Various conformable stretch bandages are known in the art, including the patent literature. While not intended to represent an exhaustive search, the following patents are nevertheless illustrative.
U.S. Pat. No. 2,379,574 of Goldthwait discloses an absorbent gauze having elasticity in both the length and cross directions. As described and claimed, the bandage is prepared by treating an open weave cotton fabric with a swelling agent for cellulose (sodium hydroxide being specifically disclosed) without applying tension to cause the fabric to shrink in all directions, thereby imparting many small spring-like crimps. The bandage is said to be self-fitting, self-tightening if applied with a slight stretch, flexible and elastic.
U.S. Pat. No. 2,404,837, also to Goldthwait, is said to be directed to a similar bandage, except that the improved elastic properties are present in only one direction at a time instead of in both directions at once. Accordingly, surface properties causing layers of the fabric to resist slipping are developed to a lesser degree (Col. 1). The bandage is prepared by allowing shrinkage to take place in only one direction while restraint is exerted to prevent shrinking in the other direction; or allowing the shrinkage to take place in both directions and then pulling the fabric back by tension in one direction.
U.S. Pat. No. 4,041,581 and a division thereof, 4,118,841 issued to Diggle disclose a method and apparatus for preparing an improved bandage gauze said to have increased crimp and bulk and a desirable degree of lengthwise stretch. Specifically, a system is described and claimed for the mechanical compressive shrinkage of woven gauze bandage in multiple-ply form in a two-roll differential speed mechanical compactor.
A particularly useful elastic bandage is described and claimed in U.S. Pat. No. 4,173,131 issued to Pendergrass, which patent will be discussed in detail hereinafter.
U.S. Pat. No. 4,775,579 of Hagy et al discloses an elastic nonwoven fabric suitable for use as a surgical bandage, which fabric comprises 15 to 80 weight percent of an elastic synthetic polymer web or net and 20 to 85 weight percent absorbent staple fibers hydraulically entangled in the elastic polymer web.
Finally, U.S. Pat. No. 4,820,572 issued to Killian et al teaches a composite elastic non-woven web comprised of a coherent matrix of meltblown fibers of a specified polyether block amide copolymer and at least one type of other fibers.
As heretofore alluded to, a particularly efficacious porous elastic bandage is described and claimed in U.S. Pat. No. 4,173,131. According to the patented teachings, a lightweight, porous knitted elastic bandage is produced from a warp of false-twist synthetic yarns with a filling inlay of regular yarns. The filling yarns are arranged in varying patterns across the warp yarns so that a portion of their length lies in looped and cursive configuration upon the surface of the bandage, and the structure is so open that overlapping layers of the bandage cling to each other in substantially non-displaceable relationship.
As stated commencing at the bottom of Col. 1:
In addition to the patent literature, conformable stretch bandages are commercially available.
For example, The Kendall Company, assignee of the present invention, manufactures and sells under their trademark "CONFORM" a lightweight bandage within the scope of the aforementioned U.S. Pat. No. 4,173,131. The CONFORM elastic bandage, which possesses moderate elasticity and softness, is described as having a unique crocheted construction which holds securely to any body contour, while still allowing freedom of movement.
Another commercially available gauze bandage, "KLING"(trademark of Johnson & Johnson) is stated to be a rolled bandage for securing hard-to-manage areas or where flexibility is important, which bandage clings to itself and is said to be soft, absorbent and flexible so that it moves with you but remains comfortable and secure.
While elastic bandages of the type disclosed in U.S. Pat. No. 4,173,131 and exemplified by the commercially available "CONFORM" bandage are highly useful for such purposes as for applying compressive pressure over a primary dressing and in general compare most favorably in performance with other elastic bandages, it is nevertheless desired to provide still better ply adhesion (shear strength).
Accordingly, stated simply, the task of the present invention is to provide crochet knitted elastic bandages produced from a warp of false twist synthetic yarns with a filling inlay of regular yarns and which are characterized by having both improved ply adhesion.